Based on observations of a discrepancy between 'hypersensitivity' reactions to docetaxel (DT) and the clinical features of allergic reactions, we explored the hypothesis that DT-induced acute hypersensitivity reactions (AHRs) have a non-allergic origin. Forty cancer patients receiving DT and 16 patients receiving other potentially allergenic chemotherapeutic agents were included in the study. All DT patients received standard pre- and post-medication. Before, during and after administration of the drugs, clinical symptoms and signs were recorded, and serial blood sampling was performed for the first 2 cycles for all patients or in all subsequent cycles in case of AHRs. Plasma histamine and serum tryptase, two established drug allergy markers, were measured. Seventy-five chemotherapy sessions were evaluable. Nine patients on DT, two on paclitaxel (PT) and one on pegylated doxorubicin experienced an AHR during the first course of chemotherapy. In all cases, heart rate remained stable or increased, while arterial pressure was unchanged or raised; no hypotension or bradycardia was noted. All episodes resolved with discontinuation of drug and did not reappear during a re-challenge with the same agent 30 min later. Tryptase levels were normal in all pre- and post-exposure samples (post-exposure: 11.32+/-35.63 microg/l, normal values <13.5 microg/l). In all but one AHR-free PT, pre- and post-exposure histamine concentrations remained normal (post-exposure: 2.86+/-11.88 nM, normal values <10 nM). No eosinophilia or basophilia was observed. We conclude that 'hypersensitivity' reactions to DT seem not to be histamine or tryptase mediated; thus, their allergenic nature should be questioned. The underlying mechanism may be related to other biological processes such as the release of vasoactive molecules or non-histamine/tryptase-mediated allergy. If the former is demonstrated by further study, the safety of DT administration will be confirmed, and the pre- and post-medication practice might be revisited.

Trastuzumab is considered effective against human epidermal growth factor receptor (HER)-2-positive breast cancer as assessed by immunohistochemistry (IHC) and fluorescence or chromogenic in situ hybridization (FISH/ CISH) on biopsy material. Trastuzumab is now approved in both the adjuvant and metastatic settings for this patient population. Because HER-2 extracellular domain (ECD) levels have been correlated with disease progression in the metastatic setting, we considered trastuzumab salvage therapy plus a taxane in heavily pretreated trastuzumab-naive relapsed breast cancer patients with high serum levels of HER-2 ECD (>15 ng/ml). All patients had previously failed at least two lines of anthracycline-and taxane-based regimens and were HER-2 negative by IHC and FISH/CISH prior to a centralized reanalysis, and were serum positive for HER-2 ECD (>15 ng/ml) at baseline. Regular serum accounts of HER-2 ECD were recorded and compared with response and survival outcomes. Twenty-two patients were finally eligible for salvage therapy. Minor responses were observed in five (23%) and stable disease (SD) was observed in 11 patients, leading to a clinical benefit rate of 73% (16 of 22 patients). The median time to progression and overall survival time were 5 (6.5 months in minor responders and SD) and 12 months, respectively; 11 and eight patients remained progression free for >6 and >12 months, respectively. Eleven and seven patients were alive at 12 and 15 months, respectively, after treatment start. Furthermore, in total, 13 (59.1%) patients obtained a biochemical response. In our study, patients with conventionally HER-2-negative disease but with expression of HER-2 ECD above the normal limit (>15 ng/ml) displayed a rapid response, both biochemically and clinically, to the trastuzumab-taxane combination. This is the first study assessing anti-HER-2-based treatment in HER-2-negative advanced breast cancer according to HER-2 ECD positivity; if our results are confirmed, additional patients with "hidden" HER-2-positive breast cancer might benefit from anti-HER-2 treatment. The Oncologist